Jacques van der Mase, an Anabaptist martyr from Brussels, was burned at the stake in 1536 or 1537 at Kortrijk (Courtrai), Belgium. He probably had be­longed to the revolutionary wing of Anabaptism and he had relations with Münsterite Anabaptists in a number of towns in the Netherlands, as The Hague, Delft, Rotterdam, Dordrecht, Gorinchem, and Geertruidenberg. After the fall of Münster in July 1535 he went to Flanders. He is one of the rare instances of revolutionary principles among the Anabaptists in Flanders and at the same time an indication of early occurrence of Anabap­tism at Kortrijk.